KR100530037B1 - Break controlling system of electric vehicle - Google Patents

Abstract

The present invention relates to a brake control system of an electric vehicle. In particular, in a brake control system combining an electric regenerative braking system and a mechanical hydraulic braking system of an existing electric vehicle, the deceleration will of the driver is determined to determine a target braking force and a predetermined regenerative braking force. After the comparison, by controlling the friction braking force by hydraulic pressure, the electric motor drive motor can be efficiently designed and the brake control system of the electric vehicle can improve the braking force and braking characteristics according to the driver's deceleration will. will be.

Description

Brake control system for electric vehicles {BREAK CONTROLLING SYSTEM OF ELECTRIC VEHICLE}

The present invention relates to a brake control system of an electric vehicle. In particular, in a brake control system combining an electric regenerative braking system and a mechanical hydraulic braking system of an existing electric vehicle, the deceleration will of the driver is determined to determine a target braking force and a predetermined regenerative braking force. After the comparison, by controlling the friction braking force by hydraulic pressure, the electric motor drive motor can be efficiently designed and the brake control system of the electric vehicle can improve the braking force and braking characteristics according to the driver's deceleration will. will be.

In general, unlike an internal combustion engine, an electric vehicle (EV) is a pollution-free vehicle that drives a driving motor with electric energy stored in a battery and runs by rotating a wheel through a power transmission device. With the depletion and serious environmental pollution problem appearing to all of humanity, the development of low pollution-free automobiles is required.

When the driving motor is stopped in the electric vehicle (particularly, when the brake pedal is pressed), the driving motor is driven in a direction in which counter-electromotive force generated by the driving motor rotating by inertial force is cut off by the battery supplied to the driving motor. It applies the braking force by applying it to the drive motor to rotate in reverse to.

That is, when the electric vehicle depresses the brake pedal while the vehicle is in progress, the electric power supplied to the driving motor is cut off, and the reverse electromotive force generated from the power supply terminal of the driving motor rotating by the traveling inertia force of the vehicle is applied to the driving motor again. The braking force is generated by causing the drive motor to rotate in reverse with respect to the traveling direction. This braking force is called 'regenerative braking'.

However, according to the regenerative braking device applied to the conventional electric vehicle as described above, since the regenerative braking amount is fixed within the proper range of the maximum output torque of the driving motor regardless of the driver's deceleration intention, it is active according to the driver's deceleration intention. There was a limit to the efficient use of energy due to no regenerative braking. In addition, since only a braking force corresponding to the predetermined regenerative braking amount is generated, a considerable time is required to brake the electric vehicle.

Therefore, in order to solve the above problems, a new brake system has been proposed in recent years by adding a general hydraulic braking device used in gasoline and diesel vehicles to the regenerative braking device of an electric vehicle.

1 is a configuration diagram showing a brake control system of a conventional electric vehicle.

As shown in Fig. 1, a brake pedal 1; A brake booster 2 for boosting the pedaling force of the brake pedal 1; A master cylinder (3) for generating hydraulic pressure by the back force of the brake booster (2); A hydraulic line 4 which transmits the hydraulic force generated in the master cylinder 3 to each wheel FR, FL, RR, and RL; Wheel cylinders 5 installed on each of the wheels FR, FL, RR, and RL to convert hydraulic action forces supplied through the hydraulic lines 4 into mechanical forces; A hydraulic modulator 6 for adjusting the pressure by increasing or reducing the braking hydraulic pressure supplied to the wheel cylinder 5; A brake pedal detecting unit 7 detecting a pressurized state of the brake pedal 1; A regenerative braking module unit including a driving motor (not shown) for supplying driving power of an electric vehicle, and performing driving and regenerative braking by forward / reversely rotating the driving motor according to a control signal of a controller 9 to be described later ( 8); It includes a control unit 9 for controlling the operation of the regenerative braking module unit 8 and the hydraulic modulator 6 in accordance with the brake detection signal provided from the brake pedal detection unit (7).

In the brake system of the conventional electric vehicle configured as described above, when the driver presses the brake pedal 1, the brake booster 2 doubles the pedaling force, and according to the action force of the brake booster 2, the master cylinder 3 Hydraulic pressure is generated, and the generated hydraulic pressure is supplied to the wheel cylinders 5 installed on the wheels FR, FL, RR, and RL along the hydraulic line 4 and the hydraulic modulator 6, thereby providing friction braking force due to general hydraulic pressure. Do this.

At the same time, the brake pedal detection unit 7 detects the stroke of the brake pedal 1 and applies the signal to the control unit 9, and the control unit 9 controls the regenerative braking module 8 connected to the axle. Signal to perform regenerative braking and energy regeneration.

However, according to the brake control system of the conventional electric vehicle configured as described above, since the electric regenerative braking force of the driving motor and the friction braking force by hydraulic pressure are combined and braked as they are, the braking force more than the target braking force intended by the driver is generated and the driver is generated. The deceleration is faster than the deceleration of the electric vehicle according to the deceleration will cause a problem to the driving safety of the vehicle, such as a shock to the driver.

The present invention has been made to solve the above-mentioned problems, an object of the present invention is to determine the deceleration of the driver in the brake control system that combines the electric regenerative braking device and the mechanical hydraulic braking device of the existing electric vehicle to determine the target braking force and By comparing the pre-set regenerative braking force and selectively controlling the friction braking force by hydraulic pressure, it is possible to efficiently design the driving motor of the electric vehicle and to improve the braking force and braking characteristics according to the driver's deceleration will. It is to provide a brake control system.

In order to achieve the above object, the brake control system of the electric vehicle of the present invention includes a hydraulic brake device and an electric vehicle including a brake pedal, a brake booster, a master cylinder, a front wheel / rear side hydraulic line and a front wheel / rear wheel cylinder. A brake control system for an electric vehicle, comprising a regenerative braking device that performs regenerative braking by a drive motor for supplying driving power, the brake control system comprising: a brake pedal detecting unit configured to sense a pressurized state of the brake pedal; An oil pressure sensing unit sensing oil pressure generated by the master cylinder; A normal open solenoid valve disposed between the master cylinder and the front wheel side cylinder; A normal closed solenoid valve provided in communication with the front wheel side hydraulic line connecting the master cylinder and the normal open solenoid valve; A relief valve connected in parallel to the normal closed solenoid valve; Control the operation of the regenerative braking device according to the hydraulic modulator for controlling the braking hydraulic pressure supplied to the rear wheel side cylinder and the brake detection signal provided from the brake pedal sensing unit, the target braking force and the detected by the hydraulic sensing unit Comparing the set regenerative braking force is characterized in that it further comprises a control unit for controlling the operation of the hydraulic modulator and the normal-open solenoid valve and the normal closed solenoid valve according to the result.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. This embodiment is not intended to limit the scope of the invention, but is presented by way of example only.

2 is a functional block diagram schematically illustrating a brake control system of an electric vehicle according to an embodiment of the present invention, Figure 3 is a hydraulic pressure for explaining the brake control system of the electric vehicle according to an embodiment of the present invention Schematic.

As shown in Figures 2 and 3, the brake control system of the electric vehicle according to the present invention, the brake pedal 100; A brake booster 150 for boosting the pedaling force of the brake pedal 100; A master cylinder 200 generating hydraulic pressure by the back force of the brake booster 150; A hydraulic pressure sensing unit 250 for detecting the hydraulic pressure generated in the master cylinder 200; Front wheel side hydraulic line 300 for transmitting the hydraulic action force generated in the master cylinder 200 to the front wheel (FR, FL); A front wheel side wheel cylinder 350 installed at the front wheels FR and FL to convert hydraulic pressure acting on the front wheel side hydraulic line 300 into a mechanical force; A normal-opened (NO) solenoid valve 400 disposed between the master cylinder 200 and the front wheel-side wheel cylinder 350 and normally open; A normal closed type (Normal-Closed, NC) solenoid valve 450 provided in communication with the front wheel side hydraulic line 300 connecting the master cylinder 200 and the normal-open solenoid valve 400; A solenoid driving unit 500 for driving a normal open solenoid valve 400 and a normal closed solenoid valve 450; A relief valve 550 connected to the normal closed solenoid valve 450 in parallel to protect the circuit due to excessive hydraulic pressure; A rear wheel side hydraulic line 600 which transmits the hydraulic force generated in the master cylinder 200 to the rear wheels RR and RL; A rear wheel side cylinder cylinder 650 installed at the rear wheels RR and RL for converting the hydraulic action force supplied through the rear wheel side hydraulic line 600 into a mechanical force; A hydraulic modulator 700 for adjusting the pressure by increasing or reducing the braking hydraulic pressure supplied to the rear wheel cylinder 650; An accelerator pedal detecting unit 750 for sensing a pressurized state of the accelerator pedal (not shown); A brake pedal detecting unit 800 for detecting a pressurized state of the brake pedal 100; A regenerative braking module unit including a driving motor (not shown) for supplying driving power of an electric vehicle, and performing driving and regenerative braking by forward / reversely rotating the driving motor according to a control signal of a controller 900 to be described later. 850); Control the operation of the regenerative braking module unit 850 according to the respective detection signals provided from the accelerator pedal detection unit 750 and the brake pedal detection unit 800, the target braking force and the detected by the hydraulic pressure detection unit 250 A control unit 900 for comparing the set regenerative braking force and operating the normally open solenoid valve 400 and the normal closed solenoid valve 450 and controlling the operation of the hydraulic modulator 700 according to the result; It includes a power supply unit 950 for supplying operating power to each unit.

In the above-described configuration, in the brake system of the electric vehicle according to the present invention, the brake pedal 100, the brake booster 150, the master cylinder 200, the hydraulic pressure sensing unit 250, the front wheel / rear wheel side hydraulic line 300 ( 600, the front wheel / rear wheel cylinders 350, 650, and the hydraulic modulator 700 are generally well known, so detailed description thereof will be omitted (for example, Korean Patent Publication No. 2002- 0073792, Korean Patent Publication No. 2002-0044334, etc.).

Normally open solenoid valve 400 is not shown, but is generally open because the plunger is configured to open the orifice by the elastic force of the spring when electricity is not applied to the solenoid. When the current is applied to the solenoid, the plunger is advanced to close the orifice flow path. In addition, the normal closed solenoid valve 450 operates in the opposite direction.

Each of the normally open / normally closed solenoid valves 400 and 450 is electrically connected to the control unit 900 through the solenoid driving unit 500 and is operated by a predetermined control signal output from the control unit 900. Done.

Although not shown, the relief valve 550 is generally coiled when the valve body closes the opening of the valve seat due to the elastic bearing force of the coil spring, and the upstream side becomes very high pressure than the downstream side. The valve body is displaced in the valve opening direction in response to the elastic bearing force of the spring, and the opening of the valve seat is opened to flow the fluid.

Although not shown, the hydraulic modulator 700 is generally configured to include an oil pump, a suction valve, a discharge valve, an accumulator, a damper, and the like to increase pressure, reduce pressure, and maintain pressure of the rear wheel cylinder 650 of the brake. Each state is controlled.

The accelerator pedal detecting unit 750 and the brake pedal detecting unit 800 may be provided in position of the accelerator pedal and the brake pedal 100, respectively, and formed of a position sensor for detecting a stroke, and the position sensor may include a variable resistor ( It is preferably made of a potentiometer, and converts the change of the electrical resistance value into a voltage according to the stroke of the accelerator pedal and the brake pedal 100, and transmits the electrical signal to the controller 900.

Although not shown, the regenerative braking module unit 850 generally drives a motor by a predetermined control signal, that is, a control signal of the controller 900, and generates a counter electromotive force by braking law when braking; A driving battery which supplies power to the driving motor by a control signal of a control unit 900; It comprises a motor control unit for controlling the operation of the drive motor and the drive battery by a control signal of the control unit 900.

The regenerative braking module unit 850 configured as described above performs regenerative braking by generating a rotational resistance at the same time as the energy regeneration operation according to the control signal of the controller 900.

Here, the regenerative braking refers to braking while absorbing the inertial force of the vehicle to go straight to the driving motor when braking the vehicle in the electric vehicle, the driving motor can store this energy in the drive battery because the counter electromotive force is generated. .

The controller 900 may be provided separately from an electronic control unit (ECU) that is responsible for the overall control of the electric vehicle.

In addition, the controller 900 receives the brake detection signal output from the brake pedal detection unit 800 when the electric vehicle is braked, converts the regenerative braking force into a predetermined regenerative braking force, and converts the regenerative braking signal corresponding thereto into the regenerative braking module unit 850. To the motor control unit.

The power supply unit 950 is preferably provided in the interior of the electric vehicle to use a conventional battery power to operate the electrical, electronic components, but is not limited to this, the battery or the drive battery of the regenerative control module unit 850 provided separately You can also use a power source.

Hereinafter, the operation of the brake control system of the electric vehicle of the present invention having the above-described configuration will be described in detail.

4A and 4B are diagrams illustrating an operating state of a brake control system of an electric vehicle according to an embodiment of the present invention. First, it is apparent that the control unit 900 mainly performs.

4A is a hydraulic flow chart for explaining a case in which the target braking force detected by the hydraulic pressure sensing unit of the present invention is smaller than the predetermined regenerative braking force.

As shown in FIG. 4A, first, when the driver presses the brake pedal 100 to decelerate or stop the vehicle, the control unit 900 receives the brake detection signal from the brake pedal detection unit 800 and sets a predetermined regenerative braking force. The regenerative braking signal corresponding thereto is transferred to the motor control unit of the regenerative braking module unit 850.

At the same time, receiving the hydraulic pressure detection signal from the hydraulic pressure sensing unit 250 calculates the target braking force, and compares the calculated target braking force with the regenerative braking force, when the target braking force is smaller than the regenerative braking force, the regenerative of the drive motor is performed. It is judged that the braking force alone can sufficiently handle the brake braking of the electric vehicle, so that friction braking by hydraulic pressure is not performed.

At this time, the control unit 900 transmits a drive control signal to the solenoid driving unit 500 to operate the normal open solenoid valve 400 and the normal closed solenoid valve 450.

That is, when the normally open solenoid valve 400 is blocked by the drive control signal of the controller 900, the hydraulic pressure generated in the master cylinder 200 does not flow into the front wheel cylinder 350, and the friction braking force by the hydraulic pressure is reduced. At the same time, the normal closed solenoid valve 450 is opened and the hydraulic pressure generated in the master cylinder 200 is transferred to the relief valve 550 via the normal closed solenoid valve 450, resulting in excessive hydraulic pressure. To protect.

On the other hand, the driving motor is generally installed on the front wheel (FR, FL) side of the two-wheel drive (2WD) electric vehicle, when generating only the regenerative braking force by the drive motor generates a braking force only on the front wheel (FR, FL) side As a result, unstable braking occurs, such as a slip phenomenon such as slippage of the tire of the electric vehicle on the road surface. Therefore, the braking force generated by the front wheel FR, FL is also applied to the rear wheels RR and RL of the electric vehicle. Should be generated.

Therefore, the control unit 900 transmits a predetermined control signal to the hydraulic modulator 700 installed in the rear wheel side hydraulic line 600, so that the hydraulic pressure generated in the master cylinder 200 is hydraulically transmitted through the rear wheel side hydraulic line 600. As it is provided to the rear wheel cylinder 650 via the modulator 700, a friction braking force is generated on the rear wheels RR and RL by the hydraulic pressure generated by the regenerative braking force generated on the front wheels FR and FL. Brake braking is possible.

4B is a hydraulic flow chart for explaining a case in which the target braking force detected by the hydraulic pressure sensing unit of the present invention is larger than the predetermined regenerative braking force.

As shown in FIG. 4B, when the driver presses the brake pedal 100 to decelerate or stop the vehicle, the controller 900 receives a brake detection signal from the brake pedal detection unit 800 and converts the brake signal into a predetermined regenerative braking force. The regenerative braking signal corresponding thereto is transferred to the motor control unit of the regenerative braking module unit 850.

At the same time, receiving the hydraulic pressure detection signal from the hydraulic pressure sensing unit 250 calculates the target braking force, and compares the calculated target braking force with the regenerative braking force, when the target braking force is greater than the regenerative braking force, the regenerative of the drive motor is performed. It is judged that the braking force alone cannot sufficiently handle the brake braking of the electric vehicle, so that the friction braking force by hydraulic pressure is performed together.

At this time, the control unit 900 does not transmit a drive control signal to the solenoid driving unit 500, so that the normal open solenoid valve 400 and the normal closed solenoid valve 450 do not operate. That is, the normal open solenoid valve 400 is in an open state, and the normal closed solenoid valve 450 is kept in a blocked state.

Accordingly, the hydraulic pressure generated in the master cylinder 200 is supplied to the front wheel side wheel cylinder 350 through the normal open solenoid valve 400 through the front wheel side hydraulic line 300 to generate a friction braking force by the hydraulic pressure.

Here, the friction braking force refers to the target braking force remaining after subtracting the regenerative braking force from the target braking force.

On the other hand, the friction braking force of the front wheel side wheel cylinder 350 by the regenerative braking force by the drive motor and the hydraulic pressure generated in the master cylinder 200 installed on the front wheel (FR, FL) side of the electric vehicle is the front wheel (FR, FL) As the braking force is generated only on the side, an unstable braking occurs such as slippage of the tire of the electric vehicle slipping on the road surface. Therefore, the front wheel (FR, FL) is also generated on the rear wheels (RR, RL) of the electric vehicle to prevent this. The braking force should be generated as much as the combined braking force combined with the regenerative braking force and the friction braking force.

Therefore, the control unit 900 transmits a predetermined control signal to the hydraulic modulator 700, so that the hydraulic pressure generated in the master cylinder 200 passes through the hydraulic modulator 700 through the rear wheel side hydraulic line 600 and then the rear wheel side wheel. As provided to the cylinder 650, the friction braking force is generated on the rear wheels RR and RL by hydraulic pressure equal to the braking force of the regenerative braking force and the friction braking force generated on the front wheels FR and FL.

Although a preferred embodiment of the brake control system for an electric vehicle according to the present invention has been described above, the present invention is not limited thereto, and various modifications are made within the scope of the claims and the detailed description of the invention and the accompanying drawings. It is possible to implement and this also belongs to the present invention.

According to the brake control system of the electric vehicle of the present invention as described above, in the brake control system combining the electric regenerative braking system and the mechanical hydraulic braking system of the existing electric vehicle to determine the deceleration of the driver to the target braking force and the predetermined By comparing the regenerative braking force and selectively controlling the friction braking force by the hydraulic pressure, the driving motor of the electric vehicle can be efficiently designed, and the braking force and the braking characteristic can be further improved according to the driver's deceleration will.

1 is a configuration diagram showing a brake control system of a conventional electric vehicle,

2 is a functional block diagram for schematically illustrating a brake control system of an electric vehicle according to an embodiment of the present invention;

3 is a hydraulic system diagram for explaining a brake control system of an electric vehicle according to an embodiment of the present invention;

4A and 4B are diagrams illustrating an operating state of a brake control system of an electric vehicle according to an embodiment of the present invention. FIG. 4A is a case in which the target braking force detected by the hydraulic pressure sensing unit of the present invention is smaller than a predetermined regenerative braking force. Figure 4b is a hydraulic flow diagram for explaining, Figure 4b is a hydraulic flow chart for explaining the case where the target braking force detected in the hydraulic pressure sensing unit of the present invention is larger than the predetermined regenerative braking force.

     *** Explanation of symbols on main parts of drawing ***

100: brake pedal, 150: brake booster,

200: master cylinder, 250: hydraulic pressure sensing unit,

300: front wheel side hydraulic line, 350: front wheel side cylinder,

400: Normally open solenoid valve, 450: Normally closed solenoid valve

500: solenoid drive unit, 550: relief valve,

600: rear wheel hydraulic line, 650: rear wheel cylinder,

700: hydraulic modulator, 750: accelerator pedal detection unit,

800: brake pedal detection unit, 850: regenerative braking module unit,

900: control unit, 950: power supply unit

Claims (1)

A regenerative braking device that performs regenerative braking by a hydraulic braking device including a brake pedal, a brake booster, a master cylinder, a front / rear hydraulic line and a front / rear wheel cylinder, and a driving motor that supplies driving power for an electric vehicle. In the brake control system of the electric vehicle made by combining, A brake pedal detecting unit detecting a pressurized state of the brake pedal; An oil pressure sensing unit sensing oil pressure generated by the master cylinder; A normal open solenoid valve disposed between the master cylinder and the front wheel side cylinder; A normal closed solenoid valve provided in communication with the front wheel side hydraulic line connecting the master cylinder and the normal open solenoid valve; A relief valve connected in parallel with the normal closed solenoid valve; A hydraulic modulator for adjusting braking hydraulic pressure supplied to the rear wheel cylinder; And Controls the operation of the regenerative braking device according to the brake detection signal provided from the brake pedal detecting unit, compares the target braking force detected by the hydraulic sensing unit with a predetermined regenerative braking force, and according to the result, the normal-open solenoid valve or And a control unit for operating the normal closed solenoid valve and controlling the operation of the hydraulic modulator.